There is generally a need for database systems to have both a high degree of security and to have great operation performance. However, achieving both these advantages at the same time is normally not possible. Databases normally operate most efficiently when using their native operation procedures. However, using this approach normally leads to a lowered security level. The degree of security provided by the native functionality differs for different databases, and can generally quite easily be manipulated. A higher degree of security would normally be achieved by using full encryption on the database, and using an external security system for accessing the database. Further, using an external security system provides a uniform and consistent security level even when using different database systems. However, such a solution would greatly reduce the operation performance of the database. Often, an external security system will lower the performance rate by a 100 times or more. Further, several previously proposed solutions, also has the drawback that it is not possible to apply it on already existing commercial databases.
There is therefore a need for an improved database system and method for controlling access to a database which provides both a high security level and a great operational performance.